pg

MODULE

pg

MODULE SUMMARY

Distributed, Named Process Groups

DESCRIPTION

This (experimental) module implements process groups. A process
group is a group of processes that can be accessed by a common
name. For example, a group named foobar can include a set
of processes as members of this group and they can be located on
different nodes.

When messages are sent to the named group, all members of
the group receive the message. The messages are serialized. If
the process P1 sends the message M1 to the group,
and process P2 simultaneously sends message M2, then
all members of the group receive the two messages in the same
order. If members of a group terminate, they are automatically
removed from the group.

This module is not complete. The module is inspired by the ISIS
system and the causal order protocol of the ISIS system should
also be implemented. At the moment, all messages are serialized
by sending them through a group master process.

EXPORTS

create(PgName) -> ok | {error, Reason}

Types:

PgName = term()

Reason = already_created | term()

Creates an empty group named PgName on the current
node.

create(PgName, Node) -> ok | {error, Reason}

Types:

PgName = term()

Node = node()

Reason = already_created | term()

Creates an empty group named PgName on the node
Node.

join(PgName, Pid) -> Members

Types:

PgName = term()

Pid = pid()

Members = [pid()]

Joins the pid Pid to the process group
PgName.
Returns a list of all old members of the group.

send(PgName, Msg) -> ok

Types:

PgName = Msg = term()

Sends the tuple {pg_message, From, PgName, Msg} to
all members of the process group PgName.

Failure: {badarg, {PgName, Msg}}
if PgName is
not a process group (a globally registered name).

esend(PgName, Msg) -> ok

Types:

PgName = Msg = term()

Sends the tuple {pg_message, From, PgName, Msg} to
all members of the process group PgName, except
ourselves.

Failure: {badarg, {PgName, Msg}}
if PgName is
not a process group (a globally registered name).